1. Field of the Invention
The present invention relates to an encoding apparatus and an encoding method using a turbo code, and more particularly, to an encoding apparatus and an encoding method using a turbo code capable of improving error correction performance, and a permutation unit and a permutation method of.
2. Description of the Related Art
Generally, digital data may contain errors during transmission due to wired/wireless link/channel noises or other data transmission. For this reason, communication systems use error correction technologies to correct errors occurred during transmission.
A turbo code is a forward error correction (FEC) technology. An encoder using Turbo Code encodes and transmits input blocks using the turbo code, thereby decreases the error occurrence rate during the transmission and corrects the errors.
The turbo code shows better performance as a minimum hamming distance (MHD) gets higher; however, this is largely affected by interleaving, that is, permutation. Hereinafter, a permutation method of turbo code will be briefly described.
First, a uniform or a regular interleaving scheme uses a rectangular matrix scheme, such that the interleaving is performed well even when an error pattern weight is 2 or 3. However, the uniform or the regular interleaving scheme does not change the decoding weight of the decoder, such that it can't improve an error correction performance by the interleaving and is largely affected by the square or rectangular error pattern.
A non-uniform interleaving scheme can disperse the error patterns well, thereby well dispersing code words of each code when the weight of the error pattern is 2 or 3, increasing the decoding weight, and exponentially improving the gain and performance of permutation.
For this reason, the non-uniform interleaving scheme is mainly applied to the turbo code. Among those, a duo-binary turbo code of an RCS standard is evaluated as a strong forward error correction technology, which almost come close limitations of Shannon. However, the duo-binary turbo code generates an error floor phenomenon at a low coding rate. Therefore, there is a need to improve the error floor phenomenon.